Koltin21，Android大厂高级面试题灵魂100问

homeFragmentPresenster.getHomeInfo()

homeRvAdapter.setData(datas)

//有数据可以滚动才可以监听滚动事件,设置标题的透明效果

rvHome.setOnScrollListener(object : RecyclerView.OnScrollListener() {

override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {

if (recyclerView != null) {

super.onScrollStateChanged(recyclerView, newState)

}

}

override fun onScrolled(recyclerView: RecyclerView, dx: Int, dy: Int) {

if (recyclerView != null) {

super.onScrolled(recyclerView, dx, dy)

}

sum += dy

if (sum > distance) {

alpha = 255

} else {

alpha = sum * 200 / distance

alpha += 55

}

Log.e(“home”, “alpha:$alpha”)

ll_title_container.setBackgroundColor(Color.argb(alpha, 0x31, 0x90, 0xe8))

}

})

}

fun onHomeSuccess() {

}

fun onHomeFailed() {

}

}

HomeFragmentPresenster.kt presenter展示层，处理相关的业务逻辑

package com.example.takeout.presenter

import android.util.Log

import com.example.takeout.model.net.TakeoutService

import com.example.takeout.ui.fragment.HomeFragment

import com.google.gson.Gson

import com.google.gson.reflect.TypeToken

import com.heima.takeout.model.beans.Seller

import com.heima.takeout.model.net.ResponseInfo

import org.json.JSONObject

import retrofit2.Call

import retrofit2.Callback

import retrofit2.Response

import retrofit2.Retrofit

import retrofit2.converter.gson.GsonConverterFactory

class HomeFragmentPresenster(val homeFragment: HomeFragment) {

val takeoutService: TakeoutService

init {

val retrofit = Retrofit.Builder()

.baseUrl(“http://localhost:8080/”)

.addConverterFactory(GsonConverterFactory.create())

.build()

takeoutService = retrofit.create(TakeoutService::class.java!!)

}

/**

• 使用异步获取数据

*/

fun getHomeInfo() {

//TOTO:要异步访问

val homeCall = takeoutService.getHomeInfo();

homeCall.enqueue(object : Callback {

override fun onResponse(call: Call?, response: Response?) {

if (response == null) {

Log.d(“HomeFragmentPresenster”, “服务器没有成功返回=====”)

} else {

if (response.isSuccessful()) {

val responseInfo = response.body()

if (responseInfo.code.equals(“0”)) {

val json = responseInfo.data

parserJson(json)

} else if (responseInfo.code.equals("-1")) {

//返回值和接口文档约定

}

} else {

Log.d(“HomeFragmentPresenster”, “服务器代码错误=====”)

}

}

}

override fun onFailure(call: Call?, t: Throwable?) {

Log.d(“HomeFragmentPresenster”, “onFailure=====”)

}

})

//有数据，成功页面

homeFragment.onHomeSuccess()

//无数据，异常页面

homeFragment.onHomeFailed()

}

/**

• 解析数据

*/

private fun parserJson(json: String?) {

//解析数据

val gson = Gson()

var jsonObject = JSONObject(json)

//附近的商家

var nearby = jsonObject.getString(“nearbySellerList”)

val nearbySellers: List =

gson.fromJson(nearby, object : TypeToken<List>() {}.type)

//其他的商家

val other = jsonObject.getString(“otherSellerList”)

val otherSellers: List =

gson.fromJson(other, object : TypeToken<List>() {}.type)

//TODO:刷新UI

//有数据，成功页面

if (nearbySellers.isNotEmpty() || otherSellers.isNotEmpty()) {

homeFragment.onHomeSuccess()

} else {

//无数据，异常页面

homeFragment.onHomeFailed()

}

}

}

ResponseInfo.kt服务端定义的数据结构

package com.heima.takeout.model.net

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ckage com.heima.takeout.model.net

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